When seismic prospecting is done in shallow bays and marshes having, for example, a water depth of up to about 6 ft., a number of data acquisition units (DAUs) which are floated about 50 meters from one another along a survey line having drop cables suspended therefrom which support and connect hydrophones thereto. Waterproof, multi-channel electrical cables extend between adjacent pairs of the DAUs so that the output signals from the hydrophones are transmitted to a recorder on a boat. The DAUs can be individually anchored to the water bottom in a suitable manner. In response to a source of acoustic energy which is created, for example, by the explosion of a charge of dynamite or an air gun in the water to the side of the survey line, the resulting acoustic waves travel down through the earth and are reflected back upward toward the surface when they encounter a boundary between two earth strata which have substantially different acoustic impedances. The arrival of the reflected acoustic waves is detected by the hydrophones, and is transmitted by the DAUs and the cables to the recorder. The survey results can be used to map the contours of the various underwater geological structures which are under the body of water, and particularly when displayed in multi-dimensional form, such maps provide valuable aids in determining those structures which might contain hydrocarbons in commercial quantities.
After the seismic data has been acquired, it is necessary to retrieve from the water all the equipment including the DAUs, the cable sections, and the hydrophones. To make waterproof connections between the ends of the multi-channel cables and the DAUs, it is a common practice to use connector assemblies that are threaded together in some fashion to achieve a fluid-tight seal. When such assemblies are disconnected by a crew member, serious problems have been encountered due to damage to the pins as the connector members are released. After release of the threads, the pins and sockets are still engaged. To achieve their release, it was common practice to rock the connector member which is located at the end of the cable from side-to-side while pulling thereon. The resultant side loading on the ferrules of the pins, which are molded and bonded in place, produced cracks in the bonds. The next time the cable and its end connections were used, salt water can leak in through these cracks and, in short order, destroyed the electrical integrity of the connector.
A general object of the present invention is to provide a new and improved electrical connector of the type described where the pins and sockets are positively released from one another as the threads which hold the connector members together are released.
Another object of the present invention is to provide a new and improved electrical connector of the type described where a shell that surrounds a body has a threaded portion that is coupled to threads of a companion receptacle and which draw the connector members tightly together to ensure a leak-proof connection.
Another object of the present invention is to provide a new and improved electrical connector assembly of the type described where the unthreading of the shell from the receptacle during disconnection provides a positive separation of the sockets and pins during a substantial portion of the travel of the shell that is necessary to unthread it from the companion threads on the receptacle, whereby release of the sockets from the pins then can be accomplished without applying damaging bending loads thereto.